1. Field of the Invention
The present invention relates to a novel blasting medium and a blasting method employing such a medium.
2. Discussion of Background
Heretofore, sand has usually been used as a blasting medium (abrasive material), but the use has been rather limited, since an installation to be used exclusively for recovery of sand is required, and a problem occurs such that sand scatters around the environment, or sand enters into a sliding part of the machine. On the other hand, sodium hydrogencarbonate (sodium bicarbonate) has heretofore been proposed as a water-soluble blasting medium (JP-B-6-69668, JP-B-7-55451, WO91/15308). However, this is directed to use of crystals of sodium bicarbonate, of which the average particle size is at most 0.5 mm, and it is used mainly for removal of coatings from the metal surfaces of aircrafts. It is used merely as a paint remover as a substitute for methylene chloride, from the viewpoint of easiness of waste treatment. Accordingly, if it is used for removal of a wall material such as mortar, for removal of an epoxy resin coating on the interior surface of a pool, for removal of coatings or putty material from vehicles, for cleaning a bogie of a vehicle, or for removal of shells from the bottom of a ship, for which sand blasting has been used, the removing or stripping ability is inadequate, and it takes time for the operation.